I'm running Big Sur and I noticed three things about Time Machine:

  1. if I format a drive as HFS+ and then I choose it for Time Machine, it gets automatically converted to APFS without asking;
  2. once a backup is completed, if I open it in Finder I can only see the data volume, as it skipped the system one;
  3. local snapshots seem to be available (I can see them via tmutil) but I cannot access them in Time Machine UI.

I would need to know if these things are "normal", please.

1 Answer 1


All three are normal for TM volumes created in Big Sur.

Explanations for 2 & 3: you won't see the system volume in the Finder, but it will be available if you need to boot from the TM volume. The only reason for doing that would be to repair or restore the source.

Local Snapshots are stored on the source and are not designed to be accessed from within the TM interface.

  • I've never upgraded to Catalina, but in Mojave I could access local snapshots in Time Machine and even restore files from them: has it changed in Big Sur? Nov 30, 2020 at 6:45
  • While I can see the system volume of my boot drive using diskutil, I cannot see the system volume of the Time Machine drive: it seems it doesn't exist at all... and, in fact, if I go to /System in the Finder and then I enter Time Machine to restore an item, I can only see the Library folder (in a previous backup, not in the current state) because it is on the data volume. In other words, it seems there's no way to go back in time in the system volume, which definitely is not what Time Machine was meant to be. I guess there's no way to do a full restore too, it should simply fail. Nov 30, 2020 at 8:33
  • 1
    Restoring a Time Machine backup changed in Big Sur. Whereas in the past you could boot Recovery and "reinstall everything" directly, now you have to reinstall macOS first followed by transferring information from the TM backup. Recover all your files from a Time Machine backup explains it. The way you get into Recovery Mode is different on Apple Silicon Macs also (tl;dr ⌘ R doesn't work on them) Dec 1, 2020 at 15:18
  • This means not having any backup of the system volume, no Time Machine history for it, no chance to restore the system volume at a certain point back in the past... did Apple really do such a **** by design? Dec 1, 2020 at 15:28
  • Yes, I suspect they want to deprive us the ability to do that. I could speculate the reason but so can you. Hint: as iOS goes, macOS follows. I'm surprised Time Machine even exists any more. Dec 2, 2020 at 16:04

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